Structures, energetics and vibrational spectra of CO2 clusters through molecular tailoring and cluster building algorithm

Abstract

Clusters of CO₂ are a subject of detailed experimental as well as theoretical investigations due to their interesting applications. In the present article, CO₂ clusters (n = 6 to 13) are studied at the MP2 level of theory. The clusters are grown using a cluster building algorithm developed by our group and the larger ones are optimized at the MP2/aug-cc-pVDZ level by employing a Molecular Tailoring Approach (MTA). Vibrational spectra of these clusters are also calculated at this level of theory within MTA. The computed vibrational frequencies for an asymmetric C–O stretch generally exhibit a blue shift with increasing cluster size. This observation is in agreement with the experimental results. MTA-single point energies for each cluster size at the MP2/aug-cc-pVTZ level are also calculated for estimating the interaction energies at the complete basis set limit.